Changes in Nature’s Balance Sheet Alcamo, Joseph; van Vuuren, Detlef; Ringler, Claudia ...
Ecology and society,
12/2005, Letnik:
10, Številka:
2
Journal Article
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Four quantitative scenarios are presented that describe changes in worldwide ecosystem services up to 2050–2100. A set of soft-linked global models of human demography, economic development, climate, ...and biospheric processes are used to quantify these scenarios. The global demand for ecosystem services substantially increases up to 2050: cereal consumption by a factor of 1.5 to 1.7, fish consumption (up to the 2020s) by a factor of 1.3 to 1.4, water withdrawals by a factor of 1.3 to 2.0, and biofuel production by a factor of 5.1 to 11.3. The ranges for these estimates reflect differences between the socio-economic assumptions of the scenarios. In all simulations, Sub-Saharan Africa continues to lag behind other parts of the world. Although the demand side of these scenarios presents an overall optimistic view of the future, the supply side is less optimistic: the risk of higher soil erosion (especially in Sub-Saharan Africa) and lower water availability (especially in the Middle East) could slow down an increase in food production. Meanwhile, increasing wastewater discharges during the same period, especially in Latin America (factor of 2 to 4) and Sub-Saharan Africa (factor of 3.6 to 5.6) could interfere with the delivery of freshwater services. Marine fisheries (despite the growth of aquaculture) may not have the ecological capacity to provide for the increased global demand for fish. Our simulations also show an intensification of present tradeoffs between ecosystem services, e.g., expansion of agricultural land (between 2000 and 2050) may be one of the main causes of a 10%–20% loss of total current grassland and forest land and the ecosystem services associated with this land (e.g., genetic resources, wood production, habitat for terrestrial biota and fauna). The scenarios also show that certain hot-spot regions may experience especially rapid changes in ecosystem services: the central part of Africa, southern Asia, and the Middle East. In general, the scenarios show a positive balance of increasing services, especially in developing countries, and a negative balance of increasing risks and tradeoffs of services. The challenge, then, is dealing with these risks so as to avoid a future curtailment of ecosystem services.
We present a simple method of probabilistic risk analysis for ecosystems. The only requirements are time series-modelled or measured-of environment and ecosystem variables. Risk is defined as the ...product of hazard probability and ecosystem vulnerability. Vulnerability is the expected difference in ecosystem performance between years with and without hazardous conditions. We show an application to drought risk for net primary productivity of coniferous forests across Europe, for both recent and future climatic conditions.
The Programme on Ecosystem Change and Society (PECS) was established in 2011, and is now one of the major international social-ecological systems (SES) research networks. During this time, SES ...research has undergone a phase of rapid growth and has grown into an influential branch of sustainability science. In this Perspective, we argue that SES research has also deepened over the past decade, and helped to shed light on key dimensions of SES dynamics (e.g. system feedbacks, aspects of system design, goals and paradigms) that can lead to tangible action for solving the major sustainability challenges of our time. We suggest four ways in which the growth of place-based SES research, fostered by networks such as PECS, has contributed to these developments, namely by: 1) shedding light on transformational change, 2) revealing the social dynamics shaping SES, 3) bringing together diverse types of knowledge, and 4) encouraging reflexive researchers.
A new fire model is proposed which estimates areas burnt on a macro‐scale (10–100 km). It consists of three parts: evaluation of fire danger due to climatic conditions, estimation of the number of ...fires and the extent of the area burnt. The model can operate on three time steps, daily, monthly and yearly, and interacts with a Dynamic Global Vegetation Model (DGVM), thereby providing an important forcing for natural competition. Fire danger is related to number of dry days and amplitude of daily temperature during these days. The number of fires during fire days varies with human population density. Areas burnt are calculated based on average wind speed, available fuel and fire duration. The model has been incorporated into the Lund‐Potsdam‐Jena Dynamic Global Vegetation Model (LPJ‐DGVM) and has been tested for peninsular Spain. LPJ‐DGVM was modified to allow bi‐directional feedback between fire disturbance and vegetation dynamics. The number of fires and areas burnt were simulated for the period 1974–94 and compared against observations. The model produced realistic results, which are well correlated, both spatially and temporally, with the fire statistics. Therefore, a relatively simple mechanistic fire model can be used to reproduce fire regime patterns in human‐ dominated ecosystems over a large region and a long time period.
A unified scheme to assign pollen samples to vegetation types was used to reconstruct vegetation patterns north of 55°N at the last glacial maximum (LGM) and mid‐Holocene (6000 years B.P.). The ...pollen data set assembled for this purpose represents a comprehensive compilation based on the work of many projects and research groups. Five tundra types (cushion forb tundra, graminoid and forb tundra, prostrate dwarf‐shrub tundra, erect dwarf‐shrub tundra, and low‐ and high‐shrub tundra) were distinguished and mapped on the basis of modern pollen surface samples. The tundra‐forest boundary and the distributions of boreal and temperate forest types today were realistically reconstructed. During the mid‐Holocene the tundra‐forest boundary was north of its present position in some regions, but the pattern of this shift was strongly asymmetrical around the pole, with the largest northward shift in central Siberia (∼200 km), little change in Beringia, and a southward shift in Keewatin and Labrador (∼200 km). Low‐ and high‐shrub tundra extended farther north than today. At the LGM, forests were absent from high latitudes. Graminoid and forb tundra abutted on temperate steppe in northwestern Eurasia while prostrate dwarf‐shrub, erect dwarf‐shrub, and graminoid and forb tundra formed a mosaic in Beringia. Graminoid and forb tundra is restricted today and does not form a large continuous biome, but the pollen data show that it was far more extensive at the LGM, while low‐ and high‐shrub tundra were greatly reduced, illustrating the potential for climate change to dramatically alter the relative areas occupied by different vegetation types.
We studied the effects of climate and land‐use change on the global terrestrial carbon cycle for the 21st century. Using the process‐based land biosphere model (LPJmL), we mechanistically simulated ...carbon dynamics for natural and managed lands (agriculture and forestry) and for land‐use change processes. We ran LPJmL with twelve different dynamic land‐use patterns and corresponding climate and atmospheric CO2 projections. These input data were supplied from the IMAGE 2.2 implementations of the IPCC‐SRES storylines for the A2, B1, and B2 scenarios. Each of these SRES scenarios was implemented under four different assumptions on spatial climate patterns in IMAGE 2.2, resulting in twelve different Earth System projections. Our selection of SRES scenarios comprises deforestation and afforestation scenarios, bounding a broad range of possible land‐use change. Projected land‐use change under different socio‐economic scenarios has profound effects on the terrestrial carbon balance: While climate change and CO2 fertilization cause an additional terrestrial carbon uptake of 105–225 PgC, land‐use change causes terrestrial carbon losses of up to 445 PgC by 2100, dominating the terrestrial carbon balance under the A2 and B2 scenarios. Our results imply that the potential positive feedback of the terrestrial biosphere on anthropogenic climate change will be strongly affected by land‐use change. Spatiotemporally explicit projections of land‐use change and the effects of land management on terrestrial carbon dynamics need additional attention in future research.
► Human well-being depends on multiple ecosystem services, many of them being underpinned by biodiversity. ► Biodiversity continues to be lost at an unprecedented rate. ► Decision-makers and ...policy-makers require sound scientific foundation to secure the planet's biodiversity and ecosystem services, while contributing to human well-being and poverty eradication. ► The new DIVERSITAS vision is built around four main research challenges to help guide the global research community towards this foundation.
DIVERSITAS, the international programme on biodiversity science, is releasing a strategic vision presenting scientific challenges for the next decade of research on biodiversity and ecosystem services: “Biodiversity and Ecosystem Services Science for a Sustainable Planet”. This new vision is a response of the biodiversity and ecosystem services scientific community to the accelerating loss of the components of biodiversity, as well as to changes in the biodiversity science-policy landscape (establishment of a Biodiversity Observing Network—GEO BON, of an Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services—IPBES, of the new Future Earth initiative; and release of the Strategic Plan for Biodiversity 2011–2020). This article presents the vision and its core scientific challenges.
Deforestation is a major threat to tropical forests worldwide, contributing up to one-fifth of global carbon emissions into the atmosphere. Despite protection efforts, deforestation of tropical ...forests has continued in recent years. Providing incentives to reducing deforestation has been proposed in the United Nations Framework Convention on Climate Change (UNFCCC) Bali negotiations in 2007 to decelerate emissions from deforestation (REDD—reduced emissions from deforestation and forest degradation). A number of methodological issues such as ensuring permanence, establishing reference emissions levels that do not reward business-as-usual and having a measuring, reporting and verification system in place are essential elements in implementing successful REDD schemes. To assess the combined impacts of climate and land-use change on tropical forest carbon stocks in the 21st century, we use a dynamic global vegetation model(LPJ DGVM) driven by five different climate change projections under a given greenhouse gas emission scenario (SRES A2) and two contrasting land-use change scenarios. We find that even under a complete stop of deforestation after the period of the KyotoProtocol (post-2012) some countries may continue to lose carbon stocks due to climate change. Especially at risk is tropical Latin America, although the presence and magnitude of the risk depends on the climate change scenario. By contrast, strong protection of forests could increase carbon uptake in many tropical countries, due to CO2 fertilization effects, even under altered climate regimes.
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